Conventional computerized devices, such as personal computers, laptop computers, and the like enable users to access (i.e., download) documents. Documents can be stored locally (i.e., on the hard drive of the a computer), or remotely, such as on a server. A server can be a local area network, available only to a particular group of users. A server can also be a publicly available server, such as the Internet.
When a user accesses a document residing on a server, typically a copy of that document is downloaded from the server to a cache on the user's computer. The time necessary for the download to occur can depend on a number of different factors, such as the connection speed of the user's computer, the bandwidth of the server, etc.
Documents can be made up of document structures. A document structure can be, for example, pages, images, annotations, structure tree, help modules, etc. Typically, document structures can be downloaded as they are needed. However, once a download begins, the download continues until it is finished, regardless of the other document structures that may be need to be downloaded.
A portable document is a document that is self-contained, and portable across any platform. That is, everything (i.e., document structures, etc.) needed to view the document (i.e., fonts, images, etc.) is bundled into the document. All users will see the same document even when viewed with different computers, different operating systems, different document viewers, etc. Essentially, the document appears the same on virtually any viewer or printed out on paper. A document that is in Portable Document Format (PDF) is an example of a portable document.